Communications networks, such as the Internet, carry a wide variety of traffic. For example, the Internet carries email, web traffic, Voice-over-IP (VoIP) traffic, multimedia traffic, and many other types of traffic. Different types of traffic place different demands on the network, as well as presenting different security challenges. For example, VoIP and other real-time data streams require packets to be consistently delivered with relatively short delays, whereas email traffic can tolerate longer delays with much more variability between packets. Additionally, several techniques to reduce unsolicited commercial email (spam) rely on recognizing and blocking email traffic from illegitimate sources. Efficient use of the network for all data types requires recognizing the needs of each traffic flow as it traverses the network.
The use of the same reference symbols in different drawings indicates similar or identical items.